A ball-and-socket joint member is already known from prior art, for example that designated under the reference CN6M, marketed by the SKF company. Such a ball-and-socket joint member usually includes an inner ring, of a general shape of revolution around a first axis, having an outer surface provided with an inner raceway, an outer ring, of a general shape of revolution around a second axis, having an inner surface provided with an outer raceway, at least one row of balls aligned circumferentially, generally two rows of balls, extending radially between the inner raceway and the outer raceway.
In this description, the terms “inner” and “outer” are considered according to the radial positions in relation to the first, respectively to the second, axis. In particular, when the first and second axes are confounded, the inner ring, respectively the inner raceway, is closer to the axes than the outer ring, respectively the outer raceway. Moreover, a surface is said to be inner when it is turned towards the axes, and outer when it is turned away from the axes.
Such a joint member authorises a movement of rotation of the outer ring around the second axis, in relation to the inner ring, or, respectively, a movement of rotation of the inner ring around the first axis, in relation to the outer ring.
The joint member also authorises a relative movement referred to as “swivelling”, corresponding to a rotation of the outer ring in relation to the inner ring around any axis (referred to as “swivel axis”) perpendicular to the first axis, or, respectively, to a rotation of the inner ring in relation to the outer ring around any swivel axis perpendicular to the second axis.
It seems that, in such a ball-and-socket joint member, the torque exerted during a swivelling movement on the outer ring is generally high, which results in wearing of this outer ring.
The invention in particular has for purpose to overcome this disadvantage, by providing an improved ball-and-socket joint member, wherein the friction and the swivelling torques applied to the outer ring are reduced.